Submitted by Paul Skolnick on Tue, 02/02/2010 - 02:39

I have some general questions about VoltaicHD workflow. I am shooting with a Canon HFX S-100 in 24p mode, and attempting to convert the MTS files to .MOV for editing in Avid or FCE. While VoltaicHD handles the transfer, it a) is frightfully slow; and b) results in HUGE files that the edit systems have trouble handling.

As to speed, 30 minutes (8 GB) of video took more than 9 hours to transcode.

As to resulting file size, the 8 GB transcoded into more than 30 GB.

My guess is that I must have something set incorrectly, but I'm not sure what. Goal is to ultimately spit out high-quality HD web videos.

Any help?

Possible Solution

Submitted by TheHerbivore on Mon, 22/02/2010 - 01:50.

I have a theory for AVCHD workflow with VoltaicHD. I work with a Canon HF10 and a depth of field adapter.

First let me explain my workflow for AVCHD in Final Cut Pro:
I log and transfer all my footage in Final Cut. I use the ProRes Proxy setting because of the smaller file sizes, which of course, makes it much easier to edit with.
When I have picture lock, I move to Soundtrack Pro for my sound editing. Then I send it back to Final Cut for color correction.
Before the next step, it is important to open Log and Transfer AGAIN and change the import settings to ProRes HQ.
When everything is perfect, in Final Cut I right click my sequence in the browser, or go to the File menu and select Media Manager.
I choose, make sequence offline, and open sequence in a new project.
That effectively makes my clips in the new sequence offline, but with the Metadata intact.
So I again right-click the sequence in the browser but select Batch Capture. Log and Transfer opens and begins recapturing just the footage I used in the sequence for my edit into ProRes HQ.
Voila! You're edit, filters, etc are still there, but now you have the final, über-quality version for archiving or what have you. Just export full quality.

I had a theory that if you imported your footage with Voltaic, you could first do it in ProRes Proxy, and then again in ProRes HQ. If Votaic had a 'Save' function that let users save their in and out points, and that linked back up to the footage on your AVCHD directory, you wouldn't have to encode TWICE, thereby saving oodles of time.
The reason you would have to encode twice, is because you need a low-quality version to edit with and a high-quality version with the same metadata to do your final batch capture into. Otherwise no NLE can recognize which clips connect to which clips. A simple 'Save' function would solve all this *wink wink hint hint*

Any questions. Just ask :)

Workflow

Submitted by justin on Tue, 02/02/2010 - 12:35.

Hi Paul,

unfortunately Voltaic is slow. 12x the footage duration for conversion time is normal. 30 min x 12 = 6hrs, so 9hrs is in the ball park.

As for file size, going from AVCHD to Apple Intermediate Codec is always a 10x file expansion. This is the same regardless of how you do it. AIC is not very compressed at all, while AVCHD is highly compressed and not suitable for general editing.

Unfortunately Final Cut Express relies on Apple Intermediate Codec as an editing format. Final Cut Pro comes with lower quality edit formats (ProRes), notably ProRes LT which is a lightweight, but still full HD format.

A high quality web video will typically run at 1280x720p at around 5Mbps. There's not much point in going to full HD on the web, unless you are planning on full-screen playback. Note that web bit rates are very low. AVCHD at 720p will run around 15Mbps, while AIC at 720p will run around 100Mbps.

You may be a bit stuck with massive file sizes when editing using Final Cut Express or iMovie. I'm not a Final Cut Pro expert, but I've found FCP more able to handle the big files than FCE.

If you get really stuck, you could try trimming your videos down with voltaic (e.g. use the preview/trim function) so that you convert the first half, then second half of the movie, giving you a smaller file size.

Regards

Justin